Joint for artificial limbs.



Nos34,9 s7. I PATENTED NOV. 6, 1906. I I G. w. LEIRMANN JOINT FORARTIFICIAL LIMBS.

APPLICATION FILED MAY. 1906.

l/VI/E/VTOR in 1 ATTORNEY I M92955; I.

GEORGE W. LEIRMANN, CLEVELAND, OHIO.

JOINT FOR ARTIFICIAL LIMBS.

Specification of Letters Patent.

Patented Nov. 6, 1906.

Application filed M y 26, 1906- Serial No. 318.960.

To all whom it may concern:

articulation of the joint.

Be it known that I, GEORGE W. LEIRMANN, a citizen of the United Statesof America, and

a resident of Cleveland, in the county of Cucyahoga and State of Ohio,have invente new and Reliable Universal Joint for Artificial Limbs, ofwhich the following is a specification.

M invention especially relates to artificial limbs ada ted to the pedalextremities and particular to the joint of the ankle.

The object o my invention is to provide a reliable universalankle-joint, one that will so closely resemble nature as to almost coverup the visual effect caused by an amputation, to provide a joint thatwill be elastic and closely simulatin the natural action of the foot andinste an having a vertical (limited) motion as we 1 as a centrifugalaction and adapted to' decline from the normal vertical position tofully the limit of ten degrees or as great an amplification of motion inany direction as is ordinarily enjoyed in the use of the natural foot.These objects and 1peculiar advantages I will hereinafter exp ain, sothat the will appear obvious to the reader.

y referring to the drawings, Which disclose the preferred form of myconstruction, it will readily be seen how I attain the objects as above,and in which- Figure 1 is a central vertical section through anartificial leg and foot having my improvement. Fig. 2 comprises twoviews of a section of felt as used to simulate the Fig. 3 is a verticalperspective view of the mechanical joint with its parts in alinement asrelated to each other, but in an unassembled condition, so as to bettershow the construction. Fig. 4 serves to show the form ofescutcheon-plate used to retain the extremities of the joint parts andprevent them from turning on their vertical axis.

Similar characters refer to similar parts throughout the drawings.

In a more particular perusal of the drawings, in Fig. 1 a is a legportion, and b a foot portion, of an artificia imb joined together withmy improved joint-bolt, comprising, primarily, three parts 0, d, and e.f and are two lates adapted to be attached to the leg and oot portions,respectively, as shown, by means of the screws 1 2 3 4 and having asquare aperture in the center of each through which the square heads ofthe joint-bolt are adapted to neatly fit and free to slide therein.Through lines A A is shown a piece of wood It, lued to the leg portionand having a square ole coinciding with the square hole in said late 9and covering all else of the plate, which is recessed into the said leg.In

. the rear of said piece of wood h I prefer to use a piece of softrubberi as a buffer for the heel action when alighting.

7' represents my preferred form. of articulas tionthat of feltand Iprefer to use it in a laminated state. Fig. 2 further shows a section ofsame.

At 7c is a iece of leather securely glued to the piece of wood It and acompanion piece lued to the nearest-lying piece of felt to allay 4iction. serves to allow of a vertical motion to the joint-bolt caused bythe impact of the foot and the ground and part of which motion is alsotaken up by the slotted link d. A piece of felt m is saturated withheavy oil and is included within the said slot in link d and serves tolubricate the pin n, servin to attach the link (1 to the lower portion eo the oint-bolt. The felt filler is better shown in Fig. 3.

A pin 0 serves to hinge the link (I to the upper portion of the joint-bolt c. The portions 0 and e are limited and fastened securely,respectively, as shown, by means of the nuts p and g, together withaccompanying washers. I prefer and have shown a plane surface on thelower extremity of the leg portionand have deviated from likeness tosame in the foot portion by adopting a rolling or undulating outline orcontour for same, having its highest or pivotal point adjacent to thecenter of gravity and the joint-bolt. Immediately in the anteriorportion I prefer a hollow, as at 1', thereby allowing for an extra layerof felt to compensate for motion due to the increased radius distancefrom the joint, while in the posterior portion I prefer a gently-slopingsurface, as shown at s.

It will appear obvious that the leg may be lengthened out for a limitedamount, and thereby compensate for any differentiation of length betweenthe limb worn and the limb retained by the wearer by placing squarewashers within the recess in the foot occupied by the square part of theportion 6 and directly under same. It is obvious, also, that it isimpossible for the foot portion to become out of alinement fore and aftThe recess Z in the leg portion ICC with regard to the leg, and with allof ugs/14$ rigidity still the leg will have a forward toandfro motionand a lateral motion, together with a combination of all possiblevariations of motions in all possible angles of declination from thevertical as enjoyed by the natural joint, while the amplification ofmotion is controlled at will of wearer by means of the take-up nut 19 inleg (1. In any action of the limb in walking the entire impact of theweight of the wearer is taken up by the felt, the resilient action ofwhich is made possible by the peculiar construction of the joint-bolt,and the jar and noise in walking is reduced to a minimum.

Having thus described the use and illustrations of my invention, what Iclaim, and wish to secure by Letters Patent, is

1. In an artificial limb; the combination of a leg portion and a footportion together with a suitable intermediate felt portion; of aplurality of metal pieces comprising a universal joint and theintermediate member of said joint adapted to hinge within the terminalmembers and move freely in all directions; and a slot within one end ofthe said intermediate piece or link together with a filling of felt,adapted to retain oil as a lubricant for the part and allowing of ayielding vertical motion to said joint, all as fully shown anddescribed.

2. In an artificial limb as described; the combination of a leg and afoot portion, together with an intermediate cushion-section; of acomposite, universal, link-joint, composed of two Y pieces or portions,0 and c, and a link d, having its two working planes at a right angleone with the other, as shown.

3. In an artificial limb as described; the combination of a leg and afoot portion, to gether with an intermediate cushion; of a pair ofplates, provided with square holes in same, centrally located; saidplates adapted to attach to the leg and foot portion respectively and auniversal, composite joint, the outermost shanks of which are s uare andare adapted to fit in the square ho es in the aforementioned plates, allas shown and described.

Signed by me at Cleveland, county of Guyahoga, and State of Ohio, this23d day of May, A. D. 1906.

GEORGE W. LEIRMANN.

Witnesses:

LEOTA GEMMILL, Mrs. ALFRED F. SMITH.

